The invention relates to a fixed displacement piston drive assembly, which utilizes double ended piston assemblies that can facilitate compression and expansion of desired gases and liquids, while maintaining or reducing torsional forces and stresses on the piston drive joints and related components, thus increasing the efficiency and life of the piston drive assembly.
Conventional compression/expansion systems often include a constant or variable speed motor and a set of single-sided pistons, in contrast to doubled ended or opposed pistons. However, conventional compression systems struggle with inefficiencies due to axial loads placed on the pistons which can lead to early failure of the pistons, cylinders or other constraint components. Additionally, single-sided pistons can also struggle with inefficiencies because work and energy is lost, or failed to be recovered, during at least one of the compression or expansion strokes.
What is needed is constraint system that enables pistons to handle higher axial loads while minimizing, or reducing, corresponding friction. Additionally, there is a need to recover losses and inefficiencies that stem from single-sided pistons, by incorporating an opposed or double ended piston configuration which can recover such losses which can typically occur during either the compression or expansion stroke of a single-sided piston configuration.
Many piston driven systems have pistons that are attached to offset portions of a crankshaft such that as the pistons are moved in a reciprocal direction transverse to the axis of the crankshaft, the crankshaft will rotate.
U.S. Pat. No. 5,535,709, defines an engine that is attached to a crankshaft with an offset portion. A lever attached between the piston and the crankshaft is restrained in a fulcrum regulator to provide the rotating motion to the crankshaft.
U.S. Pat. No. 4,011,842, defines a four cylinder piston engine that utilizes pistons connected to a T-shaped connecting member that causes a crankshaft to rotate. The T-shaped connecting member is attached at each of the T-cross arm to a double ended piston. A centrally located point on the T-cross arm is rotatably attached to a fixed point, and the bottom of the T is rotatably attached to a crank pin which is connected to the crankshaft by a crankthrow which includes a counter weight.
In each of the above examples, pistons are used that drive a crankshaft that has an axis transverse to the axis of the pistons.
Conventionally it has been established that a wobble plate, in order for necessary balance, must be restrained in a manner such that all parts of the wobble plate move in a lemniscate path. The wobble plate can be restrained, for example, by means of a stationary gear in mesh with a gear of equal number of teeth which is attached to corresponding swash plate. A disadvantage of a gear system is the relative limited strength of the gear teeth, and the need for significant and continuous lubrication. Other methods for restraining the wobble plate have also include the use of a Cardan (or a universal joint), double-Cardan, Thomson joint and constant velocity joints. Cardan, double-Cardan and Thomson joints can operate with reduced or no oil lubrication, but have limited load and speed capability which can significantly reduce the scope of applications that can utilize such a system. Constant velocity joints can handle higher speeds although require grease and also are limited in the amount of torque they can handle without becoming excessively large. Additionally, oil or other lubrications required in conventional piston drive systems, often mixes with the working fluid, which can cause additional inefficiencies. Thus, a system is needed that keeps oil, or other lubrication, separate from the working fluid, while maintaining proper lubrication of the friction inducing parts of the system.
The features and advantages of the present disclosure will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the present disclosure without undue experimentation. The features and advantages of the present disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims.